69 lines
1.6 KiB
ArmAsm
69 lines
1.6 KiB
ArmAsm
/*
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* \brief Transition between kernel/userland, and secure/non-secure world
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* \author Martin Stein
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* \author Stefan Kalkowski
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* \date 2011-11-15
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*/
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/*
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* Copyright (C) 2011-2013 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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.include "macros.s"
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.section .text
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/*
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* Page aligned base of mode transition code.
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*
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* This position independent code switches between a kernel context and a
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* user context and thereby between their address spaces. Due to the latter
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* it must be mapped executable to the same region in every address space.
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* To enable such switching, the kernel context must be stored within this
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* region, thus one should map it solely accessable for privileged modes.
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*/
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.p2align MIN_PAGE_SIZE_LOG2
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.global _mt_begin
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_mt_begin:
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/* space for a copy of the kernel context */
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.p2align 2
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.global _mt_master_context_begin
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_mt_master_context_begin:
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/* space must be at least as large as 'Cpu_state' */
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.space 32*4
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.global _mt_master_context_end
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_mt_master_context_end:
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/* space for a client context-pointer per CPU */
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.p2align 2
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.global _mt_client_context_ptr
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_mt_client_context_ptr:
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/* a globally mapped buffer per CPU */
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.p2align 2
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.global _mt_buffer
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_mt_buffer:
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/*
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* On user exceptions the CPU has to jump to one of the following
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* seven entry vectors to switch to a kernel context.
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*/
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.global _mt_kernel_entry_pic
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_mt_kernel_entry_pic:
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1: jmp 1b
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.global _mt_user_entry_pic
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_mt_user_entry_pic:
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1: jmp 1b
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/* end of the mode transition code */
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.global _mt_end
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_mt_end:
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1: jmp 1b
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